Control of electric power



y 9, 1929- E. F. w. ALEXANDERSON 1. 19.866

CONTROL OF ELECTRIC POWER Filed March 9, 1927 Inventor Ernst F Alexunderson b His Attorney.

Patented July 9, 1929.

UNITED:

"ERNST r. w.

aicExANDERsoN, or SCHENECTADY, raw-roam, assriioii m Gianna]; ELECTRIC COMPANY,;A-CORPORATION.OF unwyonxag;

', cou'rRor; Em a Applicationfiled lllareh 9,1927. SerialNo', 174,069;

My invention relates to the control of the electrical power transmitted between alternating and direct current circuits through a vapor electric device, such as a mercury rectilier provided with a the current transmitted between its cathode and anode, and has for its principal'object the provision of an improved apparatus and method whereby the grid poteutialot' such devices may be readily controlled.

It is known thatthe current transmitted between direct and alternatingcurrent circuits through ayapor electric device may be controlled by adjusting the phase relation between the anode and grid potentials of the device. Thus no current is transmitted through the device when its grid and anode potentials are 180 degrees out of phase with one another. lVhe-n the grid and anode potentials are in phase with one another. however, current is transmitted through the de-.

vice during the entire positive half cycle of the anode voltage. Between these two limits,

current starts through the device at an instant of time which gradually approaches the beginning ot the positive half cycle of the anode potential as the grid and anode potentials are brought more nearly into phase with one another. 1 I

In accordance with my invention, an improved apparatus, which is operable to produce dephased voltages and to vary the magnitudes of. these dephased voltages with respect to one another, is. provided for controllin'gthe phase relation between the grid and anode potentials of the device.

My invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

Referring to the drawings, Fig. 1 is a wiring diagram of an apparatus connected in ac cordance with my invention; and Fig. 2 is a. vector diagram relating to the operation of this apparatus.

This apparatus comprises alternating current terminals 1 and direct current terminals 2 which are interconnected through a transformer winding 3 and a vapor electric device 4. The device 4 is provided with anodes 5 which are connected to the opposite end terminals of the winding 3, with a cathode 6 which is arranged to be connected through the direct current terminals 2 and the direct grid for controlling,

age applied to t iis anode.

current load to terminal intermediate the ends of the winding 3,-and with grids 7. The apparatus for,; 'controlling the' potential-'1 of thegrids'i' comprisesa winding 8 which is a'r ranged to operate atth'c same frequency as the winding 3, is rovided with end terminals interconnected t iroughua reactor land an a ljust-'able' resistor 10, and isgprovided with an intermediate terminal connected through the I primary circuit '11 of a transformer 12 to a terminal at the'junction-betwe'en the reactor 9 and re'sistorj 10. The'trans former .12 also comprisesa secondary winding 13 p rovided'with enditerminalsconnected to the grids 7 and with an'intermediate terminal connected-to the cathode- 6; Any suitable means may be;p'rov1ded for starting and maintaining an exciting-arewithin the dev1 -e4,-

'Ihe'ope-ration of the apparatus willvbe plained'by reference to Fig.1'2 wherein the vector 8 represents the voltage 'oflthe winding 8, the vectorsfltl; and 10 respectively represent the voltagejdrops of the reactor 9 and the resistor 10 foroneadjustment'ot'this resister, the vectors 9. and 10 respectively rep- ,resentthe yoltage drops of the reactor 9 and the resistor 10for another adjustment of the resistor 10,'the vectors 9 and 10 respectivelyrepresent the voltage dropsof' the re- 9 and the resistor'10' for stillanother and the vectors actor adjustment of the .resistor, 11,. 11 and 11 represent ;the' voltages ap plied to the winding'll for the various adjustments'of the resistor. r"

It will be understood of course that the potentials of the anodes 5 alternate between positive and negative values and that current is transmitted through each anode only during a part or all of the half cycle when itspotential is'positive The instant in each.

positive haltcycle at which current starts determined by the phase relation between the potentials of this anode and the grid with which it is associated. Thus, for one adjustment of the resistor 10, the voltage 11 will be applied to this grid and current will start through the anode at a comparatively early instant in the po itive half cycle of the Volt For another adjustment of the resistor 10, however, the voltage 11 will be appliedto this grid and current will start through the anode at a later instant in the positive half cycle of the through the left hand anode, for example. is

ing a primary win of said termina adjustment in the phase of the grid potential may alsobe produced either by adjustment reactor 9 and ther'esistorilor- The embodiment of the mventionillustrat of the reactor" 9 orb adjustment "of both the terminal atthe junction of said elements and a terminal intermediate the ends of said secondaryfwinding for producing voltages haved and described herein has been selectd'for" the purpose of elearl setting forth the prin ciples involved. It wlll be apparent, however, thatthe invention is susceptible of be ng mod-. ified to meet the;diflerent cond tions encountered'iin use and-I. therefore aim to cover by the ,appe ded claims all modifications within thetrue spirit and scope of my 1nven-.

: Nvhat I claim as new and desire to secure by Letters;PatentpitheUnited states, is,- l I 1. Ilhe; combination of alternating current I terminals,.a transformer cemprising awlnding arranged to oper'ate atthe samefrequency as said alternating current ,terrn'mals, a pair of elements connected tosaid winding for producing dephas d voltages, and means con- 1 nected between a terminal at5the junction of saidelement's andaterminalintermediate the ends of said mvindingiorproducing a voltage having its phase determined by the; relative itudes of said 'dephased voltages. terminals, a transformer r,comprising a wind ing'arran ed to operate'at the same frequency aszsaidxa' ternatingcurrent. terminals, a reactor and aresistor, connected tosaid winding in seriesrwith,one;anotl1er, and means connected-betweenaa terminal, at the junction of said-reactomand, resistor and v a terminal intermediateythe-endsofsaid winding for producing a voltage, differing from the voltage sby a phase angledependent on therelationfbetween the voltage. drops of said-reactor gand said I tor. 1 L ,3.;-,The*comb'nation-o ,a pair of alternatmg current terminalszatransformer comprisalternatingqcurrent terminals and, a secondary winding, a pair of elements connected to said secondary winding for producing dcphased voltages, means connected between a ing their phases determined by the relative 'niagnitudes of said dephased voltages, and

means for adj ustin the relation between the magnitudes of said dephased voltages.

4. The combination of a pail 0 alternatifig junction of said reactor and resistor and a terminal intermediate the ends of said Winding for producing voltages differing from the voltages of said alternating current terminals by a phase angle dependent on the relation bbtweenthe voltage dropsof said reactor and connected to said voltage dropof said resistor.

v 5. The'combination of a pair of alternating current terminals, a transformercomprising a winding arranged to operate'at the same frequency as said alternating .currentft erminals, a pair 0t elements connected to said winding for producing dephased voltages, and a transformerconnccted between a tersaid esistor, and means for varying'the minal at the j unctionlof said elements and a terminal intermediate the ends of said winding for producing voltages which difi'e'r from the voltages of said alternating current terminals by a phase angle dependent on the relativemagnitudes of said dephased volta es.

In witness whereof, I have hereunto set my hand this 8th day of March,,1927.

UERNYSTF. W. Ann:(ANDERson, 

